Maryland Cannabis Laws
Maryland Marijuana DUI Laws: What Patients and Adult-Use Consumers Need to Know
Yes, you can get a DUI in Maryland for driving after using cannabis — even with a medical card, and even after the state legalized adult-use sales in July 2023. Maryland law doesn't set a blood-THC limit the way it sets a blood-alcohol limit. Instead, the question is whether cannabis impaired your ability to drive safely. If it did, you can be charged.
The Maryland Cannabis Administration advises waiting at least six hours after using cannabis before driving, and longer if you've eaten an edible. This guide walks through what Maryland law says, the penalties you face if charged, how a medical card factors in (briefly: it doesn't help here), and how to make safer decisions about cannabis and driving. None of this is legal advice — if you're facing a charge, talk to a Maryland DUI attorney.
What does Maryland law say about driving after using cannabis?
Maryland Transportation Code §21-902 is the statute that governs every impaired-driving charge in the state, whether the substance is alcohol, prescription medication, or cannabis. Unlike some states, Maryland does not set a per se THC limit — there's no number like "5 nanograms of THC per milliliter of blood equals a DUI." Instead, the law asks whether you were impaired to the point that you could not drive safely.
That distinction matters. In Colorado or Washington, a blood test above a fixed THC threshold can be enough to convict, regardless of how you actually drove. In Maryland, a prosecutor has to prove impairment — usually through a combination of officer observations, field sobriety tests, and chemical test results. The trade-off is that a "clean" blood test doesn't automatically clear you either, since impairment is judged on behavior as much as numbers.
Adult-use legalization, which took effect July 1, 2023, didn't change any of this. Maryland's possession limits and where you can buy cannabis changed; the DUI law didn't. The same §21-902 that applied to drivers in 2014 applies today, and it covers cannabis the same way it covers any other impairing substance.
What's the difference between a DUI and a DWI in Maryland?
Maryland uses both terms, and they aren't interchangeable. They describe different levels of impairment with different penalties.
DUI (Driving Under the Influence) is the more serious charge. For alcohol, it requires a BAC of 0.08 or higher (§21-902(a)). For drugs, it falls under §21-902(d) — driving while impaired by a controlled dangerous substance you're not legally entitled to use.
DWI (Driving While Impaired) is the lesser charge. For alcohol, it usually applies around a BAC of 0.07 (§21-902(b)). For drugs, §21-902(c) covers driving while "so far impaired by any drug … that the person cannot drive a vehicle safely."
Most Maryland cannabis cases are prosecuted under §21-902(c) — the DWI drug statute. The DUI drug version (§21-902(d)) typically applies when the substance is one you can't legally possess at the time, for example if you're under 21 and have no medical card.
Does a medical cannabis card protect me from a Maryland DUI?
No. A medical cannabis card lets you legally possess and purchase cannabis up to the amounts the MCA allows. It does not protect you from a DUI or DWI charge if you drive while impaired.
From the MCA directly
"If you are impaired while driving, you can get a DUI — even as a certified patient with a medical card."
— Maryland Cannabis Administration, Drugged Driving guidance
The statute itself backs this up. §21-902(c) states it is "not a defense to any charge of violating this subsection that the person charged is or was entitled under the laws of this State to use the drug." Maryland courts have applied that consistently — being a registered patient doesn't excuse impaired driving any more than a valid Ambien prescription would excuse driving while heavily sedated.
This catches some patients off guard, especially if they assumed the card worked like a doctor's note. It doesn't. What the card does do is protect your right to legally carry cannabis within possession limits, which can affect how an officer handles the stop. But once impairment is alleged, the card stops being relevant to the charge itself.
What are the penalties for a Maryland cannabis DUI?
Penalties depend on which subsection of §21-902 you're charged under and whether it's your first offense.
First offense
DWI drugs (§21-902(c)): up to 2 months in jail, $500 fine, 8 points on your license
DUI drugs (§21-902(d)): up to 1 year in jail, $1,000 fine, 12 points on your license
Second offense within 5 years
Up to 2 years in jail and a $2,000 fine
Mandatory comprehensive drug abuse assessment
Penalties are mandatory — not subject to suspension or probation under §21-902(c)(6)
Third or subsequent offense
Up to 3 years in jail and a $3,000 fine
Is a cannabis DUI a felony in Maryland?
Generally no — first and second offenses under §21-902 are misdemeanors. A cannabis DUI can become a felony in specific aggravated situations, such as causing serious injury or death while impaired (homicide by motor vehicle while impaired by a controlled substance is a separate felony statute under Maryland Criminal Law §2-505 and §2-506). For most drivers, the realistic exposure is misdemeanor-level charges with significant license and financial consequences.
License consequences
The MVA assigns points: 8 for a DWI conviction, 12 for a DUI. Eight points typically triggers a suspension hearing; 12 points can trigger license revocation. Many first-time offenders qualify for Maryland's ignition interlock program under Noah's Law, which can preserve some driving privileges in exchange for installing an interlock device for a set period.
Beyond the courtroom
A cannabis DUI also affects auto insurance rates, employment (especially anything requiring a clean driving record or a security clearance), professional licenses, and CDL eligibility. Federal rules disqualify CDL holders for impaired-driving convictions regardless of state outcome.
How long should I wait to drive after using cannabis?
The Maryland Cannabis Administration recommends waiting at least six hours after using cannabis before driving. That guidance is published directly on the MCA's Drugged Driving page and is grounded in cannabis-use research published in the American Journal of Public Health.
"If you feel different, you drive different."— Maryland Cannabis Administration
Edibles are different. The MCA notes that edibles take longer to kick in — sometimes an hour or more — and effects can last up to 12 hours. If you've eaten an edible, six hours is not enough. Plan to be done driving for the rest of the day.
Method changes the timing:
Smoking or vaping: Effects peak within minutes and typically fade within a few hours. Six hours is the MCA's recommended floor, not a ceiling.
Edibles: Slower onset, much longer duration. See our cannabis edibles dosage guide for how onset and duration scale with dose.
Tinctures: Sublingual onset is faster than edibles; effects from swallowed tinctures track edibles more closely.
Mixed with alcohol or other substances: Effects can compound unpredictably. Wait longer than you would for either alone.
For more on how long a cannabis high lasts depending on method and dose, see our evergreen guide.
What is Maryland's implied consent law for cannabis DUI?
Maryland's implied consent law, §16-205.1, says that anyone driving on a Maryland road has agreed in advance to a chemical test for alcohol or drugs if they're lawfully arrested for impaired driving. That's true for residents and visitors — the law is tied to the act of driving, not to where your license was issued.
For cannabis suspicion, breath tests don't apply (breathalyzers only detect alcohol). The relevant tests are blood and urine, which can identify THC and its metabolites.
You can refuse, but refusal triggers automatic MVA penalties separate from any criminal case:
First refusal: 270-day license suspension under Noah's Law
Second refusal: Two-year license suspension and longer ignition interlock requirements
Refusal is also admissible against you at trial as evidence of consciousness of guilt. It does not prevent prosecution — the state can still build a case on officer observations and field sobriety results.
10-day window
If your license is suspended for refusal, you have 10 days from the arrest to request a hearing with the MVA to contest the suspension. Miss that window and the suspension takes effect automatically.
Field sobriety tests (the walk-and-turn, one-leg stand, eye-tracking exam) are voluntary in Maryland — implied consent applies only to the chemical test after lawful arrest.
How do Maryland police detect cannabis impairment?
There's no roadside THC breathalyzer. Maryland police rely on layered evidence to build a cannabis DUI case:
Driving observations: Speed inconsistencies, lane drift, slow reactions at lights, near-misses
Stop observations: Odor of cannabis, red or watery eyes, delayed responses, slurred speech, visible cannabis products
Standardized Field Sobriety Tests (SFSTs): The walk-and-turn, one-leg stand, and horizontal gaze nystagmus exam — originally developed for alcohol and applied with mixed reliability to cannabis
Drug Recognition Experts (DREs): Specially trained officers who run a structured 12-step evaluation looking at vital signs, pupil response, muscle tone, and other indicators
Chemical testing: Blood or urine after arrest, measuring THC and its metabolites
THC's testing problem is real: it's fat-soluble and can stay detectable in regular users for days or weeks. A positive test doesn't prove same-day use, and a negative test doesn't prove no impairment. Maryland courts have addressed this by leaning on the impairment standard rather than a number — but the practical reality is that any THC in your system, combined with poor SFST performance, gives the state a workable case.
How long does a cannabis DUI stay on your record in Maryland?
Two records matter here, and they don't expire at the same time.
MVA driving record: Points from a DWI/DUI conviction stay on your record for two years before they no longer count toward suspension or revocation thresholds. The conviction itself stays on your MVA record permanently for the purpose of determining whether a future offense counts as a "second" or "third" — the 5-year lookback window for enhanced penalties under §21-902 doesn't erase the underlying record.
Criminal record: A DUI/DWI conviction stays on your criminal record indefinitely unless expunged. Under current Maryland law, expungement options for DUI and DWI convictions are very limited — most convictions are not eligible. Expungement law in Maryland evolves periodically, so check the current Maryland Courts guidance or talk to an attorney about whether your situation might qualify.
Outside of court records, the practical reach is what hits hardest: insurance rate increases (typically 3–5 years), employment background checks, and any role that requires a clean driving record can be affected long after the case closes.
Practical guidance for Maryland medical cannabis patients
If you use cannabis medicinally — for chronic pain, sleep, anxiety, or other conditions — the DUI law applies to you the same way it applies to anyone else. A few practical patterns help:
Tolerance does not equal safety. Research suggests regular users may still be impaired even when they don't subjectively feel it. "I feel fine" isn't a legal defense.
Plan dose timing around driving. Higher doses, edibles, or new products are best saved for days or evenings when you don't need to drive.
Consider microdosing for daytime symptom management if driving is unavoidable. Smaller doses produce less impairment — though "less" isn't "none."
Use a caregiver or rideshare when a higher dose is medically necessary.
Don't drive home from the dispensary right after consuming. Carry your cannabis in a sealed container in the trunk or rear cargo area. Open or unsealed cannabis in the passenger compartment can complicate a routine stop.
When in doubt, don't. The cost-benefit of "I'll just drive a short distance" doesn't tilt your way once an officer has reasonable suspicion.
Quick answers to common Maryland cannabis DUI questions
Can I drive with cannabis in my car in Maryland?
Yes, within legal possession limits. Keep it sealed and ideally out of the passenger compartment — trunk or rear cargo area is safest. Open containers, smell of recent use, or visible product can give an officer reasonable suspicion to investigate further.
Do I have to take a field sobriety test if a Maryland officer asks?
No. Field sobriety tests (walk-and-turn, one-leg stand, eye-tracking) are voluntary in Maryland. Implied consent applies only to the chemical test after a lawful arrest, not to roadside field sobriety tests.
Can I get a Maryland DUI for cannabis I used the day before?
Yes — if the state can prove you were impaired at the time of driving. Maryland's standard is impairment, not THC presence alone. That said, residual THC plus poor performance on field tests can support a case even when same-day use didn't happen.
Will a marijuana DUI affect my CDL?
Yes. Federal commercial driver rules disqualify CDL holders for impaired-driving convictions regardless of state outcome. A first conviction usually triggers a one-year CDL disqualification; a second is typically a lifetime disqualification.
What should I do if I'm charged with a cannabis DUI?
Talk to a Maryland DUI attorney before making statements or decisions about pleas. This page is general information, not legal advice for your specific case.